Bispectral phasor imaging using continuous-wave time-of-flight camera for scattering-scene depth recovery

Area of Science:

• Optics and Photonics
• Computer Vision
• Imaging Systems

Background:

• Time-of-flight (ToF) imaging suffers depth measurement distortion in scattering scenes due to light scattering.
• Accurate depth mapping is crucial for applications like robotics and augmented reality, but scattering poses a significant challenge.

Purpose of the Study:

• To develop a robust method for improving depth map quality in scattering scenes for Time-of-flight imaging.
• To mitigate the effects of light scattering on depth measurements using a novel bispectral approach.

Main Methods:

• Proposed a bispectral Time-of-flight system utilizing two distinct wavelengths.
• Developed a phasor-based depth-recovery algorithm that leverages wavelength-dependent amplitude and wavelength-independent phase properties of scattered light.
• Calculated the amplitude ratio of scattering phasors to nullify scattering effects.

Main Results:

• Demonstrated that scattered light amplitude is wavelength-dependent, while measured phase is wavelength-independent.
• The bispectral method significantly improved depth recovery accuracy in scattering conditions.
• The proposed approach showed robustness and low computational cost.

Conclusions:

• The bispectral Time-of-flight system and phasor-based method effectively address depth distortion caused by light scattering.
• This technique offers a practical solution for enhancing depth sensing in challenging scattering environments.
• The method provides a robust and computationally efficient way to achieve high-quality depth maps.